1. Field of the Invention
The present invention relates to a spectrally encoded coherent anti-Stokes Raman scattering (CARS) endoscope that is capable of spatially encoding spectral dispersions of two light sources having frequency difference as much as a Raman shift and overlapping two laser beams on a position where a sample to be measured is placed, thereby acquiring a spatial distribution of CARS signals.
2. Description of the Related Art
A visual observation on morphological or physiological change of diseased tissue is an important process required in early diagnosis of diseases. In particular, the wide clinical use of a laparoscope or an endoscope enabling direct observation in vivo greatly reduces lethality of patients and considerably reduces costs required for disease diagnoses. The endoscope has an advantage in that the endoscope is capable of observing an object without incision or in a minimally invasive condition in a biological research as well as in a medical research. As a result, the endoscope has been developed in various forms. Because it is characteristically required for the endoscope to be introduced into a living body to acquire an image, it is required for an endoscope probe to be as small and thin as possible, and it is also required for several optical components constituting an imaging optical system to be installed at the head part of the endoscope probe while being successfully integrated in a very small space. In most cases, a bundle of optical fibers well combed are used to guide an image acquired in vivo to the outside. However, a considerably great number of optical fibers are needed to acquire a fine image. As a result, the thickness of the endoscope probe increases as a whole. In this case, the endoscope is not appropriate for observing the inner wall of a blood vessel or internal tissue of small animals. In another approach, a micro optical mirror is installed at the head part of the endoscope probe, a laser beam introduced from the outside through a single mode optical fiber is scanned on a sample, a series of scattered light signals generated are guided to the outside through the optical fiber, and the guided light signals are processed at the outside to reproduce an image. This approach has an advantage of reducing the thickness of the endoscope probe; however, this approach encounters a fairly difficult, challengeable problem in that it is required to manufacture and integrate a high-speed scanning apparatus in a small space.